Superstorm Sandy left a lot in its wake, including one surprising phenomenon that displayed Instagram's potential as a social media powerhouse.

By Tuesday, more than 801,000 photos and images with the tag "#Sandy" had been uploaded and shared through the Facebook-owned, mobile photo-sharing app since Sandy slammed into the Eastern Seaboard last week.

Add the 485,000 photos tagged with "#hurricanesandy" and the number of images rises to nearly 1.3 million. That far eclipses the 85,000 images related to Super Bowl XLVI in February to become the biggest single event captured by Instagram users.

And those eye-catching numbers figure to draw the attention of advertisers.

"For marketers, the appeal of Instagram is imagery," said Debra Aho Williamson, principal analyst for social media marketing with the online ad research firm eMarketer.

"Images are at the root of much of brand advertising and marketers are excited about the potential of Instagram to help them deliver strong brand images in a fast-moving social environment," she said in an email.

Documenting storm Facebook and Twitter are well established as platforms for sharing experiences during major events, and storm-related posts on both were predictably high during Sandy.

But like social-networking site Pinterest, Instagram focuses on photos over text. Instagram is a mobile app that lets its 100 million users capture photos with their smartphones, brush them up with filters to make the images more artistic and instantly share them with the Instagram community, as well as on Facebook and Twitter.

In storm-battered areas where perhaps the only power available was stored on smartphones, Instagram became a shining beacon.

Users captured photos of streets strewn with debris and wrecked cars and houses crumbled into kindling wood. The photos also told a visual story of people sifting through the rubble of their lives, waiting in long lines at gas stations and donating blood.

To be sure, sometimes it is hard to tell which photos were real and which weren't. Some images tagged "#Sandy" that weren't even storm-related.

But in aggregate, the images tell an evocative story in the style of the old news magazine "Life," except in real time and curated by a vast army of citizen journalists.

Social imagery Instagram CEO Kevin Systrom, who was not available to comment for this story, told an audience at Monday's GigOm Roadmap tech conference in San Francisco that he wasn't sure how Instagram would play into the hurricane story before Sandy became "the single largest event to take place and be captured on Instagram."

He also said the storm could have been "the single largest event captured through digital images in the world ever. Imagine how many photos total were taken on the East Coast at this time. That's a really interesting moment in human history where we can look out and see things as they unfold."

EMarketer's Williamson also saw another noteworthy trend on Instagram: Some users, "especially tweens and teens," are sharing favorite quotes or their own thoughts as words overlaid on a photo or other graphical background.

"This is transforming Instagram into a social network that uses imagery, instead of just text, as the primary means of communication," she said.

New profiles Instagram also took another major step Monday by rolling out new Web profiles for its members, diverging from its mobile-only strategy.

The profiles resemble Facebook's Timeline profiles, allowing Instagram members to view photos they and others have recently shared from their mobile devices.

But instead of the static cover photo found on Facebook, the Instagram cover photo is a constantly changing collage of recently shared images.

One obvious benefit is that the Web profiles display photos on a larger screen than possible on a smart phone. Also, Instagram photos set for viewing by the general public can be seen by anyone, including non-members, which could extend the company's audience. Photos set to private can only be viewed by members.

A company blog post highlighted a profile page for apparel maker Nike, which seemed to suggest parent company Facebook was opening a potential new revenue source.

But Facebook has said it is not yet monetizing Instagram, which the social network acquired this year for $715 million in cash and stock.

Williamson said Instagram might not charge advertisers for creating company profiles, but she is certain it will eventually have paid ads that might be similar to news feed ads that Facebook is rolling out within the regular stream of wall posts.

But Instagram has "eye-catching imagery that is more appealing to mobile social media users than text is," she said. "Marketers also like the fact that the images they post on the service can be cross-posted to Facebook."